fix: resolve circular import in CMS module

Remove top-level import of cms_module from app/modules/cms/__init__.py
to break circular import chain:
  models.database -> model discovery -> cms.models -> cms.__init__
  -> cms.definition -> app.modules.base -> models.database (partial)

Replace with lazy get_cms_module() getter function.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/cms/__init__.py

@@ -27,6 +27,20 @@ Usage:
     from app.modules.cms.exceptions import ContentPageNotFoundException
 """
 
-from app.modules.cms.definition import cms_module
+# NOTE: Do NOT import cms_module at top level to avoid circular import.
+# The circular import chain is:
+#   models.database -> model discovery -> app.modules.cms.models
+#   -> app.modules.cms.__init__ -> cms_module -> app.modules.base
+#   -> models.database.admin_menu_config (partial)
+#
+# Use lazy import instead:
+#   from app.modules.cms.definition import cms_module
 
-__all__ = ["cms_module"]
+
+def get_cms_module():
+    """Lazy getter for cms_module to avoid circular imports."""
+    from app.modules.cms.definition import cms_module
+    return cms_module
+
+
+__all__ = ["get_cms_module"]